Just an update on this. I was able to prove that the upgrade was actually happening, but after the first reboot the system was rolling back and not booting into the new OS.
McAfee Support provided me with 3 additional files to add to the OSUpgrade folder located at C:\Program Files\McAfee\Endpoint Encryption\OSupgrade. With the addition of these 3 files the upgrade succeeded. I am waiting to hear back from support on whether or not they will be releasing a patch to DE 7.2.1 that will include these 3 files.